Microwave oven



FIG. 1 is front, top and right side perspective view of a microwave oven showing our new design;

FIG. 2 is a left side elevational view thereof, the right side being a mirror image;

FIG. 3 is a rear elevational view thereof; and

FIG. 4 is a bottom plan view thereof. 

The ornamental design for a microwave oven, as shown. 